だから私は休暇中のホテルの無線LANでVPNを使用しようとしていますが、何らかの理由でこの厄介な問題が発生します。数秒でVPNに接続すると、VPNが切断され、syslogに次のように表示されます。
Jun 14 20:51:14 botev-ThinkPad-T440 NetworkManager[845]: <info> Starting VPN service 'pptp'...
Jun 14 20:51:14 botev-ThinkPad-T440 NetworkManager[845]: <info> VPN service 'pptp' started (org.freedesktop.NetworkManager.pptp), PID 9778
Jun 14 20:51:14 botev-ThinkPad-T440 NetworkManager[845]: <info> VPN service 'pptp' appeared; activating connections
Jun 14 20:51:14 botev-ThinkPad-T440 NetworkManager[845]: <info> VPN plugin state changed: init (1)
Jun 14 20:51:14 botev-ThinkPad-T440 NetworkManager[845]: <info> VPN plugin state changed: starting (3)
Jun 14 20:51:14 botev-ThinkPad-T440 NetworkManager[845]: <info> VPN connection 'UCL CS VPN' (Connect) reply received.
Jun 14 20:51:14 botev-ThinkPad-T440 pppd[9783]: Plugin /usr/lib/pppd/2.4.5/nm-pptp-pppd-plugin.so loaded.
Jun 14 20:51:14 botev-ThinkPad-T440 pppd[9783]: pppd 2.4.5 started by root, uid 0
Jun 14 20:51:14 botev-ThinkPad-T440 pppd[9783]: Using interface ppp0
Jun 14 20:51:14 botev-ThinkPad-T440 pppd[9783]: Connect: ppp0 <--> /dev/pts/9
Jun 14 20:51:14 botev-ThinkPad-T440 pptp[9787]: nm-pptp-service-9778 log[main:pptp.c:314]: The synchronous pptp option is NOT activated
Jun 14 20:51:14 botev-ThinkPad-T440 NetworkManager[845]: SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
Jun 14 20:51:14 botev-ThinkPad-T440 NetworkManager[845]: SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/ppp0, iface: ppp0): no ifupdown configuration found.
Jun 14 20:51:14 botev-ThinkPad-T440 NetworkManager[845]: <warn> /sys/devices/virtual/net/ppp0: couldn't determine device driver; ignoring...
Jun 14 20:51:14 botev-ThinkPad-T440 kernel: [ 5763.841477] init: network-interface (ppp0) pre-start process (9794) terminated with status 1
Jun 14 20:51:14 botev-ThinkPad-T440 kernel: [ 5763.846659] init: network-interface (ppp0) post-stop process (9802) terminated with status 1
Jun 14 20:51:14 botev-ThinkPad-T440 pptp[9807]: nm-pptp-service-9778 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 1 'Start-Control-Connection-Request'
Jun 14 20:51:14 botev-ThinkPad-T440 pptp[9807]: nm-pptp-service-9778 log[ctrlp_disp:pptp_ctrl.c:739]: Received Start Control Connection Reply
Jun 14 20:51:14 botev-ThinkPad-T440 pptp[9807]: nm-pptp-service-9778 log[ctrlp_disp:pptp_ctrl.c:773]: Client connection established.
Jun 14 20:51:15 botev-ThinkPad-T440 pptp[9807]: nm-pptp-service-9778 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 7 'Outgoing-Call-Request'
Jun 14 20:51:15 botev-ThinkPad-T440 pptp[9807]: nm-pptp-service-9778 log[ctrlp_disp:pptp_ctrl.c:858]: Received Outgoing Call Reply.
Jun 14 20:51:15 botev-ThinkPad-T440 pptp[9807]: nm-pptp-service-9778 log[ctrlp_disp:pptp_ctrl.c:897]: Outgoing call established (call ID 0, peer's call ID 1661).
Jun 14 20:51:15 botev-ThinkPad-T440 pptp[9807]: nm-pptp-service-9778 log[ctrlp_disp:pptp_ctrl.c:950]: PPTP_SET_LINK_INFO received from peer_callid 56205
Jun 14 20:51:15 botev-ThinkPad-T440 pptp[9807]: nm-pptp-service-9778 log[ctrlp_disp:pptp_ctrl.c:953]: send_accm is 00000000, recv_accm is FFFFFFFF
Jun 14 20:51:15 botev-ThinkPad-T440 pptp[9807]: nm-pptp-service-9778 warn[ctrlp_disp:pptp_ctrl.c:956]: Non-zero Async Control Character Maps are not supported!
Jun 14 20:51:15 botev-ThinkPad-T440 pppd[9783]: CHAP authentication succeeded
Jun 14 20:51:15 botev-ThinkPad-T440 pppd[9783]: MPPE 128-bit stateless compression enabled
Jun 14 20:51:17 botev-ThinkPad-T440 pppd[9783]: local IP address 128.16.114.3
Jun 14 20:51:17 botev-ThinkPad-T440 pppd[9783]: remote IP address 128.16.114.1
Jun 14 20:51:17 botev-ThinkPad-T440 pppd[9783]: primary DNS address 128.16.6.8
Jun 14 20:51:17 botev-ThinkPad-T440 pppd[9783]: secondary DNS address 128.16.5.31
Jun 14 20:51:17 botev-ThinkPad-T440 NetworkManager[845]: <info> VPN connection 'UCL CS VPN' (IP4 Config Get) reply received from old-style plugin.
Jun 14 20:51:17 botev-ThinkPad-T440 NetworkManager[845]: <info> VPN Gateway: 128.16.11.245
Jun 14 20:51:17 botev-ThinkPad-T440 NetworkManager[845]: <info> Tunnel Device: ppp0
Jun 14 20:51:17 botev-ThinkPad-T440 NetworkManager[845]: <info> IPv4 configuration:
Jun 14 20:51:17 botev-ThinkPad-T440 NetworkManager[845]: <info> Internal Address: 128.16.114.3
Jun 14 20:51:17 botev-ThinkPad-T440 NetworkManager[845]: <info> Internal Prefix: 32
Jun 14 20:51:17 botev-ThinkPad-T440 NetworkManager[845]: <info> Internal Point-to-Point Address: 128.16.114.1
Jun 14 20:51:17 botev-ThinkPad-T440 NetworkManager[845]: <info> Maximum Segment Size (MSS): 0
Jun 14 20:51:17 botev-ThinkPad-T440 NetworkManager[845]: <info> Forbid Default Route: no
Jun 14 20:51:17 botev-ThinkPad-T440 NetworkManager[845]: <info> Internal DNS: 128.16.6.8
Jun 14 20:51:17 botev-ThinkPad-T440 NetworkManager[845]: <info> Internal DNS: 128.16.5.31
Jun 14 20:51:17 botev-ThinkPad-T440 NetworkManager[845]: <info> DNS Domain: '(none)'
Jun 14 20:51:17 botev-ThinkPad-T440 NetworkManager[845]: <info> No IPv6 configuration
Jun 14 20:51:18 botev-ThinkPad-T440 NetworkManager[845]: <info> VPN connection 'UCL CS VPN' (IP Config Get) complete.
Jun 14 20:51:18 botev-ThinkPad-T440 NetworkManager[845]: <info> Policy set 'UCL CS VPN' (ppp0) as default for IPv4 routing and DNS.
Jun 14 20:51:18 botev-ThinkPad-T440 NetworkManager[845]: <info> Writing DNS information to /sbin/resolvconf
Jun 14 20:51:18 botev-ThinkPad-T440 dnsmasq[3602]: setting upstream servers from DBus
Jun 14 20:51:18 botev-ThinkPad-T440 dnsmasq[3602]: using nameserver 128.16.5.31#53
Jun 14 20:51:18 botev-ThinkPad-T440 dnsmasq[3602]: using nameserver 128.16.6.8#53
Jun 14 20:51:18 botev-ThinkPad-T440 dbus[525]: [system] Activating service name='org.freedesktop.nm_dispatcher' (using servicehelper)
Jun 14 20:51:18 botev-ThinkPad-T440 NetworkManager[845]: <info> VPN plugin state changed: started (4)
Jun 14 20:51:18 botev-ThinkPad-T440 dbus[525]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Jun 14 20:51:20 botev-ThinkPad-T440 pptp[9787]: nm-pptp-service-9778 warn[decaps_gre:pptp_gre.c:331]: short read (-1): Message too long
Jun 14 20:51:20 botev-ThinkPad-T440 pptp[9807]: nm-pptp-service-9778 log[callmgr_main:pptp_callmgr.c:234]: Closing connection (unhandled)
Jun 14 20:51:20 botev-ThinkPad-T440 pptp[9807]: nm-pptp-service-9778 log[ctrlp_rep:pptp_ctrl.c:251]: Sent control packet type is 12 'Call-Clear-Request'
Jun 14 20:51:20 botev-ThinkPad-T440 pptp[9807]: nm-pptp-service-9778 log[call_callback:pptp_callmgr.c:79]: Closing connection (call state)
Jun 14 20:51:20 botev-ThinkPad-T440 pppd[9783]: Modem hangup
Jun 14 20:51:20 botev-ThinkPad-T440 pppd[9783]: Connect time 0.1 minutes.
Jun 14 20:51:20 botev-ThinkPad-T440 pppd[9783]: Sent 7680 bytes, received 13570 bytes.
Jun 14 20:51:20 botev-ThinkPad-T440 pppd[9783]: MPPE disabled
Jun 14 20:51:20 botev-ThinkPad-T440 pppd[9783]: Connection terminated.
Jun 14 20:51:20 botev-ThinkPad-T440 NetworkManager[845]: <info> VPN plugin state changed: stopping (5)
Jun 14 20:51:20 botev-ThinkPad-T440 NetworkManager[845]: <info> VPN plugin state changed: stopped (6)
Jun 14 20:51:20 botev-ThinkPad-T440 NetworkManager[845]: <info> VPN plugin state change reason: 0
Jun 14 20:51:20 botev-ThinkPad-T440 avahi-daemon[581]: Withdrawing workstation service for ppp0.
Jun 14 20:51:20 botev-ThinkPad-T440 avahi-daemon[581]: Withdrawing address record for 172.17.31.180 on wlan0.
Jun 14 20:51:20 botev-ThinkPad-T440 avahi-daemon[581]: Leaving mDNS multicast group on interface wlan0.IPv4 with address 172.17.31.180.
Jun 14 20:51:20 botev-ThinkPad-T440 avahi-daemon[581]: Interface wlan0.IPv4 no longer relevant for mDNS.
Jun 14 20:51:20 botev-ThinkPad-T440 avahi-daemon[581]: Joining mDNS multicast group on interface wlan0.IPv4 with address 172.17.31.180.
Jun 14 20:51:20 botev-ThinkPad-T440 avahi-daemon[581]: New relevant interface wlan0.IPv4 for mDNS.
Jun 14 20:51:20 botev-ThinkPad-T440 avahi-daemon[581]: Registering new address record for 172.17.31.180 on wlan0.IPv4.
Jun 14 20:51:19 botev-ThinkPad-T440 whoopsie[1103]: message repeated 6 times: [ online]
Jun 14 20:51:20 botev-ThinkPad-T440 whoopsie[1103]: offline
Jun 14 20:51:21 botev-ThinkPad-T440 pppd[9783]: Exit.
Jun 14 20:51:21 botev-ThinkPad-T440 NetworkManager[845]: <info> Policy set 'Hotel Broadband' (wlan0) as default for IPv4 routing and DNS.
Jun 14 20:51:21 botev-ThinkPad-T440 NetworkManager[845]: <info> Writing DNS information to /sbin/resolvconf
Jun 14 20:51:21 botev-ThinkPad-T440 dnsmasq[3602]: setting upstream servers from DBus
Jun 14 20:51:21 botev-ThinkPad-T440 dnsmasq[3602]: using nameserver 172.17.31.1#53
Jun 14 20:51:21 botev-ThinkPad-T440 NetworkManager[845]: <warn> error disconnecting VPN: Could not process the request because no VPN connection was active.
Jun 14 20:51:21 botev-ThinkPad-T440 NetworkManager[845]: <warn> (14) failed to find interface name for index
Jun 14 20:51:21 botev-ThinkPad-T440 NetworkManager[845]: nm_system_iface_flush_routes: assertion 'iface != NULL' failed
Jun 14 20:51:21 botev-ThinkPad-T440 NetworkManager[845]: <warn> (14) failed to find interface name for index
Jun 14 20:51:21 botev-ThinkPad-T440 NetworkManager[845]: SCPlugin-Ifupdown: devices removed (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
Jun 14 20:51:20 botev-ThinkPad-T440 whoopsie[1103]: offline
Jun 14 20:51:22 botev-ThinkPad-T440 whoopsie[1103]: online
Jun 14 20:51:24 botev-ThinkPad-T440 ntpdate[9867]: adjust time server 91.189.89.199 offset -0.003853 sec
Jun 14 20:51:27 botev-ThinkPad-T440 NetworkManager[845]: <info> VPN service 'pptp' disappeared
今、非常に似た問題に続いて here および here 私はwlan0とppp0のMTUも変更しようとしました。何らかの理由でwlan0の上限が2304になったため、Sudo ifconfig wlan0 mtu X
をそれ以上にしようとすると、エラーメッセージSIOCSIFMTU: Invalid argument
が表示されます。しかし、ppp0については、ほとんど何でも設定できました(30000で試して動作しました)。それにもかかわらず、これは問題の解決に役立ちませんでした。だからここで私は私のために何か変化があるかどうか疑問に思っていますか?
カーネル3.17でUbuntu 14.04を使用しています。
さて、掘り下げて実験を重ねた結果、wlan0のMTUを増やすのではなく、実際に下げる必要があることがわかりました。私が理解し、間違っている場合は修正してくださいという理由は、おそらくルータまたは途中のスイッチの1つがより低いMTUを持っているためです。したがって、パケットを正しく送信しますが、私の推測はVPNサーバーは、VPNパケットからMTUのみを認識し、そのMTUで応答します。着信パケットが大きすぎるため、彼らがこのルーターにヒットしたとき、それはあきらめます。繰り返しますが、それはこの問題に関する私の仮説です。どれだけ下げるか、正確には言えません。最初は1412でしたが、最終的には1400と1200よりも1000で最も安定していたので、それを守ります。もしそれがあなたに起こったら、ちょっと試してみてください。
私は数分前にこの問題を抱えていました、それが私がそれを解決した方法です:
Sudo ifconfig ppp0 mtu 1300
このコマンドは、このセッションでのみppp0接続のMTUサイズを変更しました。
接続にこの設定を永続的に使用する場合は、/ etc/network/if-up.d /ディレクトリに新しいファイルを作成します例:
Sudo vi /etc/network/if-up.d/ppp0-mtu
コンテンツで:
#!/bin/sh
if [ "$IFACE" = "ppp0" ]; then
Sudo ifconfig ppp0 mtu 1300
fi
このファイルを実行可能にし、VPN接続を今すぐ確認する
Sudo chmod a+x /etc/network/if-up.d/ppp0-mtu
Tracerouteを使用して、ホストへのパスの下位mtuを検出できます。コマンドは:traceroute <Host> --mtu
私の場合、低いMTUは1280だったので、1200を使用してルーター構成でvpnを作成しました。